In vivo phosphorylation of the somatostatin 2A receptor in human tumors.

摘要: Hormone-stimulated receptor internalization and desensitization occur widely in the G protein-coupled (GPCR) family. A critical first step both these processes is thought to be phosphorylation, a reaction which has been extensively characterized cell culture. However, little known about GPCR phosphorylation vivo. The somatostatin (SS) subtype (sst)2A distributed human neuroendocrine tumors, SS analogs are commonly used target this for therapy diagnosis. In cultured pituitary cells sst2A rapidly phosphorylated internalized after hormone binding. aim of present study was go one crucial further characterize state tumors using newly developed gel-shift assay. from somatostatinoma completely phosphorylated. contrast, only unphosphorylated that were not exposed autocrine stimulation. Both vivo cells, correlated with its subcellular localization: mostly intracellular, whereas localized at surface. These results demonstrate ligand-stimulated tissue situ, providing toward better understanding regulation Analysis promises provide sensitive indicator effectiveness diagnostic therapeutic situations tumor patients.